From the Kovel's newsletter -
Russell Pritchard III, who gained TV fame on the Antiques Roadshow with the appraisal of a valuable sword that the "owner" claimed to use to cut watermelons, is in the news again. He used the TV publicity to enhance his reputation, then cheated his clients while appraising or selling their antiques. He was serving a 4-to-8-year sentence in prison when he had to appear in court in October in a new case. Following a plea bargain, he was sentenced to 4 to 8 more years for yet more crimes, the extra years to be served concurrently with his earlier sentence. But the plea bargain means he also has to repay over $65,000 to his latest victims.
This is just further proof that you need to be careful about who you have do your appraisals and who you have selling your antiques and collectibles.
An honest appraiser will NEVER offer to purchase the item they are appraising. If they do run the other way and take that appraisal with a grain of salt.